Conventionally, a structural object, such as a solar panel and a house, is placed on a foundation installed on the ground surface in order to be always level with the ground. However, the structural object or the like and the foundation may be sedimented or tilted due to their weights when the ground for installing the structural object or the like is a soft ground, such as a wetland and a peatland.
Consequently, proposed is an invention related to a pile foundation that prevents sedimentation or tilt of a structural object or a foundation on a soft ground by fixing the foundation to the ground surface by driving a plurality of driving piles.
For example, the specification of U.S. Pat. No. 5,039,256 proposes a pile foundation including a cylindrical body filled with concrete or cement and including a plurality of driving piles penetrating through the cylindrical body (Patent Literature 1). According to Patent Literature 1, the pile foundation can be carried and reused as a foundation of another structural object after removal of the structural object or the like.